The accuracy of voltage reference determines the maximum achievable performance of almost all mixed-signal and radio-frequency (RF) systems. The increasing demand of modern high-performance circuits such as voltage regulators, high-resolution data converters, and precision measurement systems, requires a highly accurate reference voltage.
Nowadays, both the gate-source voltage of a metal-oxide-semiconductor field-effect transistor (MOSFET) and the base-emitter/diode voltage (VBE) of a bipolar junction transistor (BJT) are widely utilized to generate the reference voltage. Typically, the VBE of a BJT is better characterized over temperature and varies less than the threshold voltage and mobility of a MOSFET. However, the VBE of a BJT has nonlinearity over a temperature range, which causes difficulties in achieving superior low temperature dependency of the voltage reference.
Accordingly, there remains a need for an improved voltage reference generator design that utilizes the VBE of BJTs and provides a superior accurate reference voltage without temperature dependency.